Large quantities of ammonia-nitrogen wastewater are produced during the production processes of nickel-cobalt smelting, ternary precursor manufacturing, rare earth smelting, tungsten and molybdenum smelting and other industries. The wastewater has high ammonia-nitrogen concentration and contains coexisting pollutants such as heavy metals, salts and organic matter, causing great environmental harm. Conventional ammonia-nitrogen wastewater treatment technologies including breakpoint chlorination, steam stripping ammonia distillation and gas permeable membrane method generally suffer from poor treatment efficiency, high treatment cost, secondary pollution and other problems when treating complex high-concentration ammonia-nitrogen wastewater.Moreover, these technologies fail to realize resource recovery of ammonia. Research and development of low-cost and resource-oriented treatment technologies tailored for complex high-concentration ammonia-nitrogen wastewater in the non-ferrous metal industry are of great significance for addressing ammonia-nitrogen pollution in relevant enterprises and advancing their green development.
Targeting complex high-concentration ammonia-nitrogen wastewater produced by nickel-cobalt smelting, ternary precursor production, rare earth smelting, tungsten and molybdenum smelting and other sectors, this project developed a low-energy, high-efficiency steam stripping and rectification ammonia removal technology with ammonia resource recovery on the basis of systematic pollution source analysis. Energy consumption during the ammonia removal process was effectively reduced through operational simulation optimization of the steam stripping and rectification process and the development of energy-saving processes. Meanwhile, skid-mounted integrated complete sets of equipment for steam stripping and rectification ammonia removal were developed, enabling high equipment integration and shorter project construction periods. The research outcomes have been converted and applied in engineering projects across multiple industries. By comprehensively considering the collaborative treatment of ammonia-nitrogen wastewater and ammonia-containing waste gas, in-plant recycling of recovered ammonia resources, deep pollutant removal, and compliant discharge of wastewater and waste gas, the project effectively addresses the challenges of low-cost treatment and resource utilization of complex high-strength ammonia-nitrogen wastewater in China's non-ferrous metal industry.
The project has obtained 6 authorized invention patents and 11 utility model patents, and formulated 2 national standards.
The project achievements have been successfully applied to complex ammonia-nitrogen wastewater treatment in the ternary precursor, nickel-cobalt, tungsten-molybdenum and rare earth industries. More than 60 demonstration projects have been built, with an annual wastewater treatment capacity exceeding 14 million tons. The total sales revenue in the past three years reached 150.97 million yuan, covering over 70% of the production capacity in the ternary precursor industry. The project research and application of its achievements have markedly improved the technical level of ammonia-nitrogen wastewater treatment in China's non-ferrous metal industry, providing technical support for industrial wastewater emission reduction and green sustainable development.
